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Can kit foxes and red foxes produce offspring?

Can kit foxes and red foxes produce offspring?


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Can a kit fox (Vulpes macrotis) and a red fox (Vulpes vulpes) together produce offspring?

Would such a hybrid be fertile?


Yes, a red fox and a kit fox could produce hybrid offspring, but it would be sterile.

Sterile red fox / arctic fox (V. lagopus) hybrids have been bred for the fur trade for decades (source).

Arctic foxes are quite closely related to kit foxes, and both species are equally distantly related to red foxes, so since one can produce hybrids then the other should be able to as well. Here's a screenshot from onezoom.org showing their relation. (Arctic fox = Vulpes lagopus)

Red fox / kit fox hybrids have not been observed in the wild, and kit foxes are not widely kept in captivity except in zoos, so I am not aware of any record of such hybrids. It would likely take intentional effort on the part of a fox breeder to produce them.


Animal Diversity Web

Vulpes cana , Blanford's fox, is found from Israel throughout the mountainous regions of the middle east to Afghanistan. The range of this species likely covers all the middle-eastern countries, although populations may be discontinuous. They are known from Iran, Pakistan, Afghanistan, Turkistan (Kazakhstan), Israel, Oman, United Arab Emirates, and Saudi Arabia, and are expected to occur throughout a wider range, including Eritrea, Sudan, and Yemen. (Yom-Tov and Geffen, 1999)

Habitat

Vulpes cana is found in semi-arid steppes and mountains. This species prefers areas with steep, rocky slopes, cliffs, and canyons. Historically, Blanford's foxes were considered to avoid hot lowlands as well as cooler uplands. However, they have been observed near the Dead Sea in Israel, where they are found in cultivated areas where melons, Russian chives, and seedless grapes are grown. Blanford's foxes occur up to elevations of about 2000 meters. The most important habitat feature for Blanford's foxes seems to be the presence of dry creek beds. Dens are chosen in areas with large rock piles. (Yom-Tov and Geffen, 1999)

  • Habitat Regions
  • temperate
  • terrestrial
  • Terrestrial Biomes
  • desert or dune
  • savanna or grassland
  • mountains
  • Other Habitat Features
  • agricultural
  • Range elevation 2000 (high) m 6561.68 (high) ft

Physical Description

Blandford's foxes are small foxes with large ears and long, bushy tails with long, dark guard hairs. They range in mass from 1.5 to 3 kg, and in head to tail length from 70 to 90 cm (tail mean length is 323 mm, body mean length is 426 mm. Males and females are similar in appearance. The snout is slender. Vulpes cana has cat-like movements and appearance. Coloration is black, brown, or grey, and is sometimes blotchy. The flanks are lighter than the back, which has a black stripe running down it, and the underside is yellow. The tip of the tail is usually dark but can be white. Males have 3 to 6% longer forelegs and bodies than females. (Nowak, 1999 Yom-Tov and Geffen, 1999)

  • Other Physical Features
  • endothermic
  • homoiothermic
  • bilateral symmetry
  • Sexual Dimorphism
  • male larger
  • Range mass 1.5 to 3 kg 3.30 to 6.61 lb
  • Average length 426 mm 16.77 in

Development

Reproduction

Vulpes cana is monogamous. (Nowak, 1999)

Blanford's foxes typically mate from December to February. They are strictly monogamous. The gestation period is 50 to 60 days, after which the female gives birth to a litter of 1 to 3 kits. The altricial young are nursed for 30 to 45 days. Young become sexually mature between 8 and 12 months of age. (Geffen, et al., 1992 Nowak, 1999 Yom-Tov and Geffen, 1999)

  • Key Reproductive Features
  • iteroparous
  • seasonal breeding
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • viviparous
  • Breeding interval Blanford's foxes give birth once each year.
  • Breeding season Blanford's foxes breed during December and January, and give birth between March and April.
  • Range number of offspring 1 to 3
  • Average number of offspring 2 AnAge
  • Range gestation period 50 to 60 days
  • Range weaning age 30 to 45 days
  • Range age at sexual or reproductive maturity (female) 8 to 12 months
  • Range age at sexual or reproductive maturity (male) 8 to 12 months

Females nurse their young for 30 to 45 days. Young are dependent on their mothers until they can forage on their own. Foxes have relatively altricial young, and usually give birth to them in a secluded den, where they can develop under the care of their mother. Because the mating system of Blandford's foxes is monogamous, and breeding pairs maintain minimally overlapping ranges, the male may also be considered to provide some care to the offspring, even if only in the form of maintaining an area from which food is supplied. Males have been observed grooming juveniles. Young remain in their natal range until the October or November in the year of their birth. (Nowak, 1999)

  • Parental Investment
  • altricial
  • pre-fertilization
    • provisioning
    • protecting
      • female
      • provisioning
        • female
        • female
        • provisioning
          • female
          • male
          • female
          • provisioning
            • female
            • male
            • female

            Lifespan/Longevity

            Average lifespan of Blandford's foxes is 4 to 5 years, and does not exceed 10 years in the wild. Old age and rabies are the primary recorded causes of mortality. (Yom-Tov and Geffen, 1999)

            Behavior

            Blanford's foxes are strictly nocturnal, solitary hunters. They do not exhibit a change in their daily activity with season. They generally become active soon after dusk and are active throughout the night. (Geffen, et al., 2005 Geffen, et al., 1992 Nowak, 1999)

            In Israel Blanford's foxes occur at population densities up to 2 per square kilometer. They are one of the few fox species to regularly climb, scaling cliffs with ease. Their especially long tail is used as a counter balance when jumping and climbing. (Geffen, et al., 2005)

            • Key Behaviors
            • terricolous
            • nocturnal
            • motile
            • sedentary
            • solitary
            • Average territory size 1.6 km^2

            Home Range

            Foraging home range averaged 1.1 square kilometers, plus or minus 0.7 square kilometers. Monogamous pairs occupy territories of 1.6 square kilometers, with little overlap between territories. (Geffen and MacDonald, 1992)

            Communication and Perception

            Like other canids, Blanford's foxes have keen eyesight, sense of smell, and hearing. They communicate with chemical cues and with vocalizations.

            • Communication Channels
            • acoustic
            • chemical
            • Perception Channels
            • visual
            • tactile
            • acoustic
            • chemical

            Food Habits

            Blanford's foxes are omnivorous, eating mostly insects and fruit. Prey includes insects such as beetles, locusts, grasshopper, ants, and termites. Primary wild fruits eaten are two species of caperbush ( Capparis cartilaginea and Capparis spinosa ), Phoenix dactylifera , Ochradenus baccatus , Fagonia mollis , and Graminea species. Fecal samples have up to 10% vertebrate remains as well. In Pakistan they have been recorded eating agricultural crops, including melons, grapes, and Russian olives. (Geffen, et al., 2005 Geffen, et al., 1992 Nowak, 1999)

            Blanford's foxes hunt alone the majority of time. Even mated pairs tend to forage independently. They rarely cache food. (Geffen, et al., 2005)

            Blanford's foxes seem to rarely drink water, meeting their water needs through the foods they eat. (Geffen and MacDonald, 1992 Geffen, et al., 2005)

            • Primary Diet
            • omnivore
            • Animal Foods
            • mammals
            • insects
            • Plant Foods
            • fruit

            Predation

            The main predator of these foxes is humans, although one case of a Blanford's fox being killed by a red fox (Vulpes vulpes) has been recorded. Blanford's foxes are not hard to catch, showing little fear of traps or humans. (Geffen, et al., 2005 Yom-Tov and Geffen, 1999)

            Ecosystem Roles

            Blanford's foxes help to control rapidly growing small mammal populations by preying on mammals such as rodents. They may have a similar effect on insect populations. Because they are frugivorous, they likely play some role in dispersing seeds. (Geffen, et al., 1992 Yom-Tov and Geffen, 1999)

            Economic Importance for Humans: Positive

            The pelts of Blanford's foxes are valuable and they are hunted. Because of their diet, this species probably controls rodent and insect populations which might have a negative impact on crops. (Yom-Tov and Geffen, 1999)

            • Positive Impacts
            • body parts are source of valuable material
            • controls pest population

            Economic Importance for Humans: Negative

            Blanford's foxes cause domestic crop damage in some areas. (Geffen and MacDonald, 1992)

            Conservation Status

            Trapping and hunting have caused a large decline in the numbers of these foxes. They are protected throughout Israel, as the majority of their habitat is in protected areas. Development in other parts of their range may pose a risk to populations. (Nowak, 1999)

            Other Comments

            Mitochondrial DNA evidence suggests that Blanford's foxes and fennec foxes are sister taxa. (Geffen, et al., 2005)

            Contributors

            Tanya Dewey (editor), Animal Diversity Web.

            Marty Heiser (author), University of Wisconsin-Stevens Point, Chris Yahnke (editor), University of Wisconsin-Stevens Point.

            Glossary

            living in sub-Saharan Africa (south of 30 degrees north) and Madagascar.

            living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

            uses sound to communicate

            living in landscapes dominated by human agriculture.

            young are born in a relatively underdeveloped state they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.

            having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

            uses smells or other chemicals to communicate

            having markings, coloration, shapes, or other features that cause an animal to be camouflaged in its natural environment being difficult to see or otherwise detect.

            in deserts low (less than 30 cm per year) and unpredictable rainfall results in landscapes dominated by plants and animals adapted to aridity. Vegetation is typically sparse, though spectacular blooms may occur following rain. Deserts can be cold or warm and daily temperates typically fluctuate. In dune areas vegetation is also sparse and conditions are dry. This is because sand does not hold water well so little is available to plants. In dunes near seas and oceans this is compounded by the influence of salt in the air and soil. Salt limits the ability of plants to take up water through their roots.

            animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor the fossil record does not distinguish these possibilities. Convergent in birds.

            offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).

            Having one mate at a time.

            having the capacity to move from one place to another.

            This terrestrial biome includes summits of high mountains, either without vegetation or covered by low, tundra-like vegetation.

            the area in which the animal is naturally found, the region in which it is endemic.

            an animal that mainly eats all kinds of things, including plants and animals

            breeding is confined to a particular season

            reproduction that includes combining the genetic contribution of two individuals, a male and a female

            uses touch to communicate

            that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

            A terrestrial biome. Savannas are grasslands with scattered individual trees that do not form a closed canopy. Extensive savannas are found in parts of subtropical and tropical Africa and South America, and in Australia.

            A grassland with scattered trees or scattered clumps of trees, a type of community intermediate between grassland and forest. See also Tropical savanna and grassland biome.

            A terrestrial biome found in temperate latitudes (>23.5° N or S latitude). Vegetation is made up mostly of grasses, the height and species diversity of which depend largely on the amount of moisture available. Fire and grazing are important in the long-term maintenance of grasslands.

            uses sight to communicate

            reproduction in which fertilization and development take place within the female body and the developing embryo derives nourishment from the female.

            References

            Geffen, E., R. Hefner, P. Wright. 2005. "Blanford's fox (Vulpes cana)" (On-line). IUCN Canid Specialist Group. Accessed September 27, 2007 at http://www.canids.org/species/Vulpes_cana.htm.

            Geffen, E., D. MacDonald. 1993. Activity and Movement Patterns of Blandford's Foxes.. Journal of Mammalogy , 74(2): 455-463.

            Geffen, E., D. MacDonald. 1992. Small Size and Monogomy: Spatial Organization of Blandford's Foxes, *Vulpes cana*. Animal Behaviour , 44: 1123-1130.

            Geffen, E., H. Reuven, D. MacDonald, M. Ucko. 1992. Diet and Foraging behavior of Blandford's Foxes, *Vulpes cana*, In Israel. Journal of Mammalogy , 73(2): 395-402.

            Nowak, R. 1999. Walker's Mammals of the World . Baltimore and London: John Hopkins University Press.


            Fox Reproduction

            Even though the fox doesn’t live in a pack, they will find each other when it is time for mating. What is very interesting is that once a pair have mated they will continue to do so every year afterwards until one of them die. They will only mate with each other and not with other fox out there.

            They may often meet up during the course of the year to share food, for grooming, or for small periods of social interaction. This behavior is different from other types of animals that only find each other when it is time for the mating to take place. They give off powerful scents that help them to find each other.

            During the mating season the male fox will do all he can to defend his partner. Should other males try to come into contact with her they will battle. This can result in one of the males dying in the process. It is hard for the younger males to find a partner out there due to the power and protection of the older males. They must find young females that don’t already have a mating partner.

            Two foxes fighting eachother

            In many areas the fox is able to mate all year long. However, due to the vegetation and the temperatures they mainly do so in the early winter months. The males stick around to help the female out with the young. The gestation period is about 53 days. There are usually 4 or 5 young born at a time with each litter. They are born in the spring time. These young are called kites.

            They are born in a den where they can be protected from predators out there. Just about anything that the female can find will be used for her den. Sometimes it is one that another fox used the year before. Most of the time they are underground, but some fox make dens in trees.

            They are very vulnerable during the first few weeks of life. They are both deaf and blind when they are born. They also have very little hair so they need her body to keep them warm. If she has to leave then there is a good chance they won’t be able to survive.

            The mother will stay with them to protect them. She also offers them milk from her body. The male has to go get food for her so she can stay there. He also does what he can to protect the young from predators. When they are about a month old they will come out of the den.

            Kit fox in the wild, Indiana

            They will start to eat meat and continue to drink milk. Over the course of time they will drink less and less from their mother. By the summer time they are able to hunt on their own. They will spend plenty of time playing with each other but that also helps them to develop strength and skill. They will play tug of war with food and spend time chasing each other around.

            They will be full grown by Autumn and the young kites will start fighting among themselves. The playful activities of their youth has given way to aggressiveness and the quest for survival. That is when they will go their separate ways and find their own place in the world.

            The mortality rate for the fox is very high. More than half will die before they are 10 months old. Many fox don’t live more than a few years in the wild due to the conditions. However, they can survive up to 14 years in the wild with the right conditions. They have been known to live up to 20 years in captivity.


            When Do Foxes Mate?

            The breeding season for most foxes starts around December-January and lasts until February. Foxes use multiple dens, one of them being a natal/maternal den. After breeding, they will move to their natal den, where the baby foxes will be born and raised.

            All animals have different mating seasons. Most larger animals, with longer gestation periods, mate in fall or winter and give birth in the spring. While smaller animals with shorter gestation periods mate in spring and summer, however, this is not the case with most foxes.


            Foxes are omnivores who hunt mainly small rodents, birds and rabbits. However, they will occasionally eat vegetables, fruit, mice, and fish.

            Foxes have excellent senses. They can hear an animal underground, and pounce where they think the animal is going!

            Foxes are omnivores, hunting small rodents, birds, and rabbits, but also eating vegetable and fruit.

            Foxes can make 12 different vocal sounds. Kits can produce 8 sounds.

            A fox's tail is also known as a brush.

            A fox can live up to 10-12 years in captivity, but only about 3 years in the wild.


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            Can kit foxes and red foxes produce offspring? - Biology

            Kingdom: Animalia
            Phylum: Chordata
            Class: Mammalia
            Order: Carnivora
            Family: Canidae
            Genus: Vulpes
            Species: V. pallida

            Reproduction: After a gestation period of about 53 days, the Pale Fox gives birth of 3 - 6 kits. Each kit weighs about 2.64 ounces at birth. They are weaned onto solid foods from 6 - 8 weeks.

            Vulpes pallida edwardsi

            Vulpes pallida harterti

            Vulpes pallida oertzeni

            Vocalizations: According to the ones I met, they seem to be just as vocal in captivity as Fennecs, expressing loud shrieks of joy when excited. The same gekkering of Fennecs can also be heard from these similar desert foxes, and when mating in the spring, their noises are almost a constant drone.

            Source Accessed and modified 5/28/2010 http://en.wikipedia.org/wiki/Pale_Fox

            Sources Accessed and modified 4/30/2011: http://www.iucnredlist.org/apps/redlist/details/23051/0

            Kingdom: Animalia
            Phylum: Chordata
            Class: Mammalia
            Order: Carnivora
            Family: Canidae
            Genus: Vulpes
            Species: V. pallida

            Reproduction: After a gestation period of about 53 days, the Pale Fox gives birth of 3 - 6 kits. Each kit weighs about 2.64 ounces at birth. They are weaned onto solid foods from 6 - 8 weeks.

            Vulpes pallida edwardsi

            Vulpes pallida harterti

            Vulpes pallida oertzeni

            Vocalizations: According to the ones I met, they seem to be just as vocal in captivity as Fennecs, expressing loud shrieks of joy when excited. The same gekkering of Fennecs can also be heard from these similar desert foxes, and when mating in the spring, their noises are almost a constant drone.

            Source Accessed and modified 5/28/2010 http://en.wikipedia.org/wiki/Pale_Fox

            Sources Accessed and modified 4/30/2011: http://www.iucnredlist.org/apps/redlist/details/23051/0

            Kingdom: Animalia
            Phylum: Chordata
            Class: Mammalia
            Order: Carnivora
            Family: Canidae
            Genus: Vulpes
            Species: V. pallida

            Reproduction: After a gestation period of about 53 days, the Pale Fox gives birth of 3 - 6 kits. Each kit weighs about 2.64 ounces at birth. They are weaned onto solid foods from 6 - 8 weeks.

            Vulpes pallida edwardsi

            Vulpes pallida harterti

            Vulpes pallida oertzeni

            Vocalizations: According to the ones I met, they seem to be just as vocal in captivity as Fennecs, expressing loud shrieks of joy when excited. The same gekkering of Fennecs can also be heard from these similar desert foxes, and when mating in the spring, their noises are almost a constant drone.

            Source Accessed and modified 5/28/2010 http://en.wikipedia.org/wiki/Pale_Fox

            Sources Accessed and modified 4/30/2011: http://www.iucnredlist.org/apps/redlist/details/23051/0

            Kingdom: Animalia
            Phylum: Chordata
            Class: Mammalia
            Order: Carnivora
            Family: Canidae
            Genus: Vulpes
            Species: V. pallida

            Reproduction: After a gestation period of about 53 days, the Pale Fox gives birth of 3 - 6 kits. Each kit weighs about 2.64 ounces at birth. They are weaned onto solid foods from 6 - 8 weeks.

            Vulpes pallida edwardsi

            Vulpes pallida harterti

            Vulpes pallida oertzeni

            Vocalizations: According to the ones I met, they seem to be just as vocal in captivity as Fennecs, expressing loud shrieks of joy when excited. The same gekkering of Fennecs can also be heard from these similar desert foxes, and when mating in the spring, their noises are almost a constant drone.

            Source Accessed and modified 5/28/2010 http://en.wikipedia.org/wiki/Pale_Fox

            Sources Accessed and modified 4/30/2011: http://www.iucnredlist.org/apps/redlist/details/23051/0

            There are five recognized subspecies of the Pale Fox

            Vocalizations: According to the ones I met, they seem to be just as vocal in captivity as Fennecs, expressing loud shrieks of joy when excited. The same gekkering of Fennecs can also be heard from these similar desert foxes, and when mating in the spring, their noises are almost a constant drone.

            Reproduction: After a gestation period of about 53 days, the Pale Fox gives birth of 3 - 6 kits. Each kit weighs about 2.64 ounces at birth. They are weaned onto solid foods from 6 - 8 weeks. As will all foxes (except the Russian Domesticated ones), kits should be taken from the mother around 10-20 days, and hand reared for the tamest offspring possible. Kits should be socialized as much as they can with dogs, cats, and children before going to their forever homes. Any fox kits also need to be handled, have their feet, faces and mouth touched when they are kits so they are not uncomfortable with this as adults.

            Diet: In the wild, they would be omnivores, eating mice, plants, insects, and fruits and veggies if possible, so their diet must reflect this in captivity. Pale Foxes are new to the captive pet trade so it is unknown whether they need larger amounts of taurine than other foxes, but it is safe to assume their dietary needs are similar to Fennecs. You can read more about a good diet on the 'Diet & Adopting' page.

            Range: The Pale Fox's range extends throughout the middle of Africa, extending north by the Sahara Desert, and overlapping the Fennec Fox's area. They generally tend to avoid other foxes, but like all foxes, like to dig and make extensive burrows underground to keep safe from predators. There are many threats to their range, including habitat loss as the primary source, and land development and predators. As humans colonize and develop more and more land, the foxes become more spread out, often not coming into contact with other foxes often enough to breed.

            Anatomy: Interestingly enough, Pale Foxes have grinding molars like Swift Foxes do, which show that they eat not strictly meat in the wild but plant life and possibly fruit and veggies as well. However, due to their teeth, you can see the majority of them have a more carnivorous shape, similar to felines, which would suggest they eat more meat and less vegetation than Swift Foxes in the wild. We need a wider study of these elusive foxes in the wild to be conclusive about their dietary habits.

            Though they have similar personalities in vocal calls and pack mentality that Fennecs do, the interesting thing is that they share similarities with body shape and structure to Swift Foxes and Kit Foxes, which live across the world from them.


            Natural History

            This arctic fox looks a lot like a swift fox.

            Classifying the various dog species has become a bit contentious in recent years.

            Assays of various types of DNA has called into question the validity of many assumed and proposed species.

            For example, a study that involved a large sample of nuclear DNA from coyotes and wolves from many different populations found that the s0-called red wolf (supposed Canis rufus) is actually almost entirely coyote in its make-up. It does have some wolf ancestry, but this wolf ancestry comes from the Holarctic wolf (Canis lupus), not any supposed endemic North American wolf species.

            Now, wolves are fairly charismatic animals. They have quite a following in the popular culture–there is even a “wolfaboo” subculture on the internet– and in many ways, they have come to symbolize the modern conservation movement. People know that dogs are derived from wolves, and most people are willing to accept that dogs are part of the wolf species, even if there is still some institutional and cultural resistance to that notion.

            Science knows a lot about wolves, and the popular culture knows a lot about them, too.

            However, wolves are not the only wild dogs in which genetic analyses may reveal that species status is a bit more blurred than one might expect.

            Let’s take three foxes in the genus Vulpes.

            Vulpes is the big fox genus that currently includes almost everything called a fox in the Old World– the exception is the bat-eared fox (Otocyon). The red fox (Vulpes vulpes) is the most widespread of the genus, but there are several lesser known species, like the Tibetan and Blandford’s fox.

            Among these less known species are the kit fox (Vulpes macrotis) and the swift fox (Vulpes velox). Both of these foxes are found in Western North America, and there is a huge debate about whether these foxes represent a single species or two distinct species.

            This swift fox looks very much like the arctic fox at the top of this post.

            Now, at the crux of classifying these species is figuring out how closely related they are to their closest relative, which is, surprisingly, the arctic fox (Vulpes lagopus). Traditionally, the arctic fox has been placed in its own genus (Alopex), but the great preponderance of the genetic evidence shows that it belongs in the genus Vulpes.

            These foxes all have 54 chromosomes, and the swift and kit foxes regularly interbreed in West Texas and New Mexico, where the two “species” have overlapping ranges. Dragoo and Wayne (2003) examined kit and swift fox morphology and nuclear and mitochondrial DNA, and they found that the bulk of the evidence suggests that kit and swift foxes represent a single species. The authors contend that most of the greater genetic diversity within arid land foxes is actually result of them not dispersing great distances from their natal territories. Over time, populations in certain localities wind up with very distinct genetic characters, which might resemble those of a unique species. Animals that travel a great distance from their natal territories, like lions and wolves, tend not to have such distinctiveness within a local population. There was always a gene flow across wolf and lion populations that may not exist at the same extent with smaller, less mobile species.

            Animals identified as kit and swift foxes regularly interbreed in parts of New Mexico and West Texas. For whatever reason, hybrids have not been confirmed in southern Colorado and Western Kansas, where their ranges also overlap.

            Now, the notion that swift and kit foxes are part of the same species is not universally accepted, and this is where the arctic fox comes into play.

            Mercure (1993) examined the mitochondrial DNA of kit, swift, and arctic foxes and found that kit and swift foxes different from each other as much as they differ from arctic foxes. At the time, arctic foxes were still listed as belonging to their own genus, and this study was used as evidence to suggest that swift and kit foxes really were unique species. (Wayne was also an author of this study.)

            However, now that we know that arctic foxes are actually in the genus Vulpes, we have another issue that needs to be considered.

            Yes. I’m aware that mtDNA studies can be quite flawed. They examine only maternal inheritance, and very often, these studies have unusual biases. For example, initial mtDNA studies underestimated the date when forest and savanna elephants, which are now classified as separate species, split from each other.

            But it doesn’t mean that these studies are inherently useless. When combined with studies that look at more of the genome than mtDNA, they can provide an interesting picture about the evolution of a species.

            And here, I think these two studies are suggesting something quite radical:

            Not only are swift and kit foxes the same species, the arctic fox is part of this same species.

            Now, going with this classification is very contrary to what is generally accepted.

            Arctic foxes are believed to have evolved in Europe 200,000 years ago. That is when they first appear in the fossil record, and the ancestral swift fossils have been dated to 500,000 years ago. The Mercure study strongly suggests that arctic foxes evolved in North America, even though the earliest fossil remains were found in Europe.

            However, it is also possible that the ancestral swift fox fossils are not in the same lineage as modern swift and kit foxes and that they actually evolved from the arctic fox. Traditional accounts of arctic fox evolution trace them to a common ancestor it share with the red fox, Vulpes alopecoides.

            It is possible that arctic, swift, and kit foxes all radiated from that ancestor, or arctic foxes are actually the ancestors of the swift and kit foxes. Perhaps, these foxes of arid and semi-arid lands are nothing more than arctic foxes that have adapted to a very different climate.

            Further, there are several relatives of the swift/kit fox and arctic fox in Asia– the corsac and Tibetan fox. They are relatives, but they aren’t as closely related as swift/kit foxes are to arctic foxes. The fact that these three have such a close relationship with each other is really quite interesting.

            The truth is we simply don’t know how these three foxes evolved, but it is clear that they are very similar to each other.

            In fact, they differ less from each other in terms of their morphology than different breeds of dog or even different subspecies of wolf do. It is very likely that fertile hybrids can be produced with arctic foxes and either swift and kit foxes. Arctic foxes live well to the north of where both swift and kit foxes are found, so no wild hybrids have been documented.

            Thus, it might be more useful to think of them as representing a single species in which some populations have specialized adaptations. Kit foxes living in desert environments have big ears and pale coats, while arctic foxes have pelts that change colors depending upon the season.

            More research must be performed on these three foxes, and the possibility that the represent a single species with three specialized subspecies has to be considered.

            We know far less about the evolutionary relationships of these three foxes than we do about wolves, but they appear to have the same problem that wolves do. Wolf taxonomy is always in flux these days, mainly because the studies don’t reflect what has always been assumed.

            But it may be that wolves are not the only part of the dog family that might have these sorts of surprises in their DNA.

            To me it is obvious that this foxes are different species from wolves, and because arctic foxes produce only infertile hybrids with red foxes, it pretty obvious that they aren’t the same species either. It’s when you start to find a great deal of interfertility between two wild “species” that are also as distantly related to each other as they both are to a third species that one really should start to reconsider the taxonomy.

            Perhaps the most parsimonious action would be to declare a single species for kit, swift, and arctic foxes.

            I know that this is an extreme minority positions, but I think this reflects what has been found thus far.


            Damage and Damage Identification

            Foxes may cause serious problems for poultry producers. Turkeys raised in large range pens are subject to damage by foxes. Losses may be heavy in small farm flocks of chickens, ducks, and geese. Young pigs, lambs, and small pets are also killed by foxes. Damage can be difficult to detect because the prey is usually carried from the kill site to a den site, or uneaten parts are buried. Foxes usually attack the throat of young livestock, but some kill by inflicting multiple bites to the neck and back. Foxes do not have the size or strength to hold adult livestock or to crush the skull and large bones of their prey. They generally prefer the viscera and often begin feeding through an entry behind the ribs. Foxes will also scavenge carcasses, making the actual cause of death difficult to determine. Pheasants, waterfowl, other game birds, and small game mammals are also preyed upon by foxes. At times, fox predation may be a significant mortality factor for upland and wetland birds, including some endangered species. Rabies outbreaks are most prevalent among red foxes in southeastern Canada and occasionally in the eastern United States. The incidence of rabies in foxes has declined substantially since the mid-1960s for unexplained reasons. In 1990, there were only 197 reported cases of fox rabies in the United States as compared to 1,821 for raccoons and 1,579 for skunks. Rabid foxes are a threat to humans, domestic animals, and wildlife.


            What Is the Life Cycle of the Red Fox?

            Red foxes mature sexually and produce a litter at about 1 year of age. Pups are blind and helpless at birth and remain with parents for roughly half a year. Red foxes typically pair monogamously.

            Red foxes produce a single litter each year, typically in the spring. The vixen enters oestrus for 3 weeks, and she and the male mate several times during that period. Kits are usually born 49 to 58 days later. While litters of 13 kits are possible, most litters have roughly four to six offspring.

            Kits are deaf and blind and lack teeth at birth, and they weigh less than 1/4 pound. Their eyes and ears begin to function at about 2 weeks of age. Red fox kits nurse for 3 to 4 weeks before the mother begins weaning them to solid food, although a vixen lactates for 6 weeks. By 6 to 7 months of age, fox kits reach adult size, and some vixens are reproductively mature at 9 months.

            Most red foxes form monogamous pairs, and both males and females take part in caring for offspring. Help from the father is essential for the first several weeks as the mother remains with the kits to provide warmth. DNA analysis from some fox populations shows some amount of polygamy and incest.